Abstract: A DC OF cable has its main insulation composed of a composite insulation tape comprising a low dielectric loss film and kraft paper (PPLP). 1-10 sheets of kraft paper are wound on the PPLP main insulation as a layer on the inside and/or the outside thereof.

Abstract: A paper-polymeric material, laminated tape, an electric cable insulated with such tape and a method of making the tape. The tape includes a film of polymeric material to at least one surface of which a paper tape comprising cellulose fibers is bonded by contacting the paper tape at room temperature with the film heated to a temperature above its melting temperature. Prior to contacting the paper tape with the heated film, fibrils are caused to project from at least one surface of the paper tape by subjecting it to a high voltage, electrostatic field. In the laminated tape, the fibrils are embedded in the material of the film to provide an improved bond between the film and the paper tape.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: A composite tape for forming at least part of the insulation of a high voltage electrical cable, particularly an oil-filled cable, and a cable including such insulating tape. The composite tape includes at least one layer of paper tape having a borate or silicate weight content in the range form 0.1 to 3% of the weight of the paper bonded to at least one surface or the surfaces of a film of bi-oriented polymeric plastic material by a copolymer layer which has a thickness of from about 1-10 microns. The thickness of all the plastic material in the composite tape is in the range from 10 to 30% of the total thickness of the tape. Preferred polymeric materials are polypropylene and polymethylpentene. A bonding material can be propylene-ethylene copolymer.

Abstract: An insulating polyolefin laminate paper and a method for producing such a paper in which first and second fiber paper layers are laminated to a polyolefin film layer. The fiber paper layers have an impermeability of 20 to 4000 Gurley-seconds. At least one of the fiber paper layers is mechanically deformed in such a manner that irregularities are produced having a depth of 2 to 50% of the thickness of the fiber paper layer. The mechanical deformation is accomplished prior to lamination. Before lamination, the water content of the fiber paper layers is controlled to be no more than 4%. Preferably, the thickness of the fiber paper layers is at least 30 microns. Furthermore, an electric power supply cable includes an insulating polyolefin laminate paper as an insulating layer.

Abstract: An oil-immersion electrically insulated cable of high performance is constructed by wrapping a conductor with insulation formed by winding on the conductor polypropylene film having a density in the range of 0.905 to 0.915 g/cm.sup.3, a birefringence in the range of 0.020 to 0.035, a ratio of strengths in two axial directions (tensile strength in the longitudinal direction/tensile strength in the lateral direction) in the range of 5 to 15, and impregnating the insulating layer with an insulating oil, preferably DDB oil.

Abstract: An oil-filled electric cable in which the solid insulation is formed, at least in part, by separately applied, alternate layers of cellulose paper tape and of film tapes made of a plastic. Prior to application of the tapes around the cable conductor, the moisture content of the paper tape is selected and the swelling of the plastic tape by the oil after application is adjusted, if necessary, such as by immersing the plastic tape in the oil prior to application, so that the swelling of the plastic tape by the oil in the formed cable is offset by the shrinkage of the paper tape during drying of the cable. Also, apparatus for pre-swelling the plastic tape.

Abstract: An electrically insulating laminate paper for an electric apparatus to be wound in a wet state on a conductive material and thereafter impregnated with oil, which is characterized by that water drops having a wide particle size distribution are scattered on the surface of the electrically insulating laminate paper comprising an integrated assembly composed of a plastic film and fiber papers bonded to each other to moisten said fiber papers.

Abstract: The invention concerns an improvement in taped cables having large diameter and suitable for use at voltages up to and over 1000 kV. The taping of one or more layers is wound according to a double-start or multi-start helix, said helix having an inclination less than 75.degree..

Abstract: The present invention relates to a laminated insulating paper formed of cellulose paper or papers which is adhered to at least one side of cross-linked silicone grafted polyolefine film and to an oil-filled (OF) cable which insulated by the laminated insulating paper. The laminated insulating paper has outstanding peel strength as well as excellent non-solubility and anti-swelling properties in insulating oils.

Abstract: A cryogenic power cable of a cryoresistive type having a conductor which is cooled with a cooling medium to permit large capacity power transmission by reducing thereby the electric resistance and the joule loss of the conductor. The temperature of the cable core is controlled through an ingenious arrangement comprising the conductor which incorporates therein a passage for the cooling medium, an electric insulation layer made of an ordinary electric insulating material and a thermal insulating material layer. The cable not only makes ultra-high voltage transmission of 500 to 1000 KV possible but also is advantageous on account of a simple and economic structure.